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Undocumented Immigration To State Fell Sharply In Early 1990s, Study Suggests

First Study to Measure Annual Net Flow of the Undocumented to California Reveals Large Fluctuations Over Time

Undocumented Immigration to California: 1980-1993

SAN FRANCISCO, California, September 24, 1996–The number of undocumented immigrants arriving in California dropped sharply during the early years of this decade, decreasing to under 125,000 per year between 1990 and 1993 after swelling to well over 200,000 annually in the late 1980s.

These are the principal findings of a unique study being released today by the Public Policy Institute of California (PPIC). The research effort, headed by demographer Hans Johnson, is the first to measure net annual flows of undocumented immigrants, in this case into California. It demonstrates that undocumented immigration is a complex phenomenon of ups and downs rather than the inexorable stream assumed in political debate and popular discussion.

Undocumented immigration added a net of between 1,300,000 and 2,200,000 residents to the state s population from 1980 to 1990. This accounts for between 22 percent and 31 percent of the state s population growth during the period. But the movement was anything but steady. The flow was at relatively low levels in the first few years of the decade, averaging under 100,000 per year. It surged later in the 1980s, only to subside again in the early 1990s. Data are not yet available to measure what has happened from 1994 to the present.

Why did undocumented immigration plunge in the early 1990s? The principal driver was probably changing economic conditions, the California recession, Johnson contends. But it may also reflect the ebbing of the wave of undocumented immigrants joining relatives who were eligible for amnesty. The peak flow in the late 1980s may have been a one-time phenomenon related to IRCA (Immigration Reform and Control Act of 1986).

These annual estimates provided by the new PPIC study are expected to help policy makers identify the forces behind undocumented immigration, evaluate the effectiveness of control efforts, and ultimately assess the impact on government services and the state economy.

To generate the estimates, Johnson developed a two-step method. First, he estimated the total changes in the California population over the study period using census data and created annual estimates using various indicators of population size. Next he determined the components of annual change, drawing on a wide variety of sources including birth and death records, Immigration and Naturalization Service data on foreign legal immigration, and such indicators of domestic migration as drivers license address changes and tax return data. When he subtracted the legal components from the estimates of annual population change, the result was the annual flow of undocumented immigrants.

To accommodate the inevitable imprecisions in the data, including possible census undercounts, Johnson provides a range rather than single estimates for each year covered by the study. The general pattern of undocumented immigration is apparent across all of the ranges, however.

In addition to measuring undocumented immigration, the analysis also provides estimates of domestic migration flows to and from California. From the last half of the 1980s to the early 1990s, the number of people leaving the state increased dramatically while the number moving to the state decreased dramatically. This net decline in domestic migration is surprising given the state’s strong job growth during much of this period.

The Public Policy Institute of California is an independent, nonprofit organization dedicated to nonpartisan research on economic, social and political issues which affect California. David W. Lyon is President.


Steven Bliss
General Media
Lori Pottinger
PPIC Water Policy Center Media
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